Now let us give preliminaries on the topological and metric entropy.
In this paper topological entropy of \(f\)  will be denoted \(h_{\mathrm {top}}\)  and if \(\mu \)  is an \(f\) -invariant probability measure, then associated metric entropy is denoted \(h_{\mu }(f)\) . For definitions and basic facts on invariant measures and entropy we refer the reader to standard textbooks, e.g. [1]}. Below we briefly recall a few most important facts used in this paper.
